So first thing is: What games? What parts? Does he need a Windows OS? A monitor with keyboard and mouse?
>>> Let me know if you would like to change anything!
Parts Link: http://pcpartpicker.com/p/22aRi
CPU: AMD FX-6300 3.5GHz 6-Core Processor ($117.97 @ SuperBiiz)
Motherboard: Asus M5A97 LE R2.0 ATX AM3+ Motherboard ($69.99 @ Microcenter)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory ($72.99 @ Newegg)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($59.94 @ OutletPC)
Video Card: Gigabyte Radeon HD 7870 2GB Video Card ($183.98 @ Newegg)
Case: Cooler Master HAF 912 ATX Mid Tower Case ($49.99 @ Microcenter)
Power Supply: Corsair Enthusiast 650W 80+ Bronze Certified ATX Power Supply ($83.98 @ Newegg)
Optical Drive: LG GH24NS95 DVD/CD Writer ($15.00 @ Newegg)
Total: $653.84
(Prices include shipping, taxes, and discounts when available.)
Hope this helps!